Wood-pole-protective means



Jun 3, 1930.

G. w.' HAMILTON WOOD POLE PROTECTIVE MEANS Filed June '17; 1929 y vwantoz 650x 5 m HAMILTON Patented June 3, 1930 GEORGE WELLINGTON HAMILTON, OF EVANS TON, ILLINOIS WOOD-POLE-PROTECTIVE Application filed June 17,

The invention relates to power line installation and has special reference to means for protecting the wooden poles used for supportmg transmission lines against damage in the event of a flash-over which may occur as the result of lightning.

It is well known that wood pole construction is used largely for the benefit derived 1 thermore, if the hardware, suspension devices,

braces, etc. on the pole are not grounded or partially grounded through a gap, the wood is almost certain to be burned or otherwise damaged by the li htning discharge.

It is with the a ove' facts in view that I have devised the present invention which has for its principal object the provision of a protective gap or pluralityof gaps on the ole, at least certain of the metallic elements orming the gap or gaps being grounded, the purpose being to ermit the lightning discharge to jump t e gap and pass to the ground.

An important object of the invention is to provide a protective device for this purpose which will not interfere with or detract from the insulating value of the wood but which will at the same time act to safeguard the same against burnin or other destruction.

A more specific o jectpf the invention is to provide a protective device embodying 'arcmg horns mounted upon the cross bar of a wooden supporting pole structure, certain of the arcing horns being associated and electrically connected with the metallic elements which support the insulators which in turn carry the transmission lines or conductors, and the others being suitably grounded in same convenient manner.

An additional object of the'invention is to provide 11 arrangement of this character which simple and inexpensive to make and install, positive in action, efficient in service and a general improvement in the art.

0 the attainment of the foregoing and the cross arm 2, these those in eac palr 1929. Serial No. 371,680.

other objects and advantages, the invention preferably consists in the details of construction and the arrangement and combination of parts to be hereinafter more fully described and claimed, and illustrated in the accompanying drawing in which:

Figure 1 is a side elevation of a wooden supporting structure of a transmission line showing an embodiment of the invention, and

Figure 2 is a top plan view.

Referring more particularly to the drawing, the numeral. 1 designates upright wooden supporting poles which carry a wooden cross arm 2 from which are suspended strings or chains of suspension insulators 3 carrying clamps 4 which support the conductors 5. While the invention can conjunction with insulators of the pin type, it lends itself very readily to that type of im stallation where suspension insulators are employed for which reason this type is illustrated. 'lhe strings of insulators 3 are here shown as hanging from bolt-like members 6. It is customary to provide metal braces? for braces being appropriately mounted upon the poles 1 as shown at 8 and being secured to the cross arm as by bolt members 9 passing therethrough. Usually, the poles are guyed as shown at 10 though th1s is an immaterial detail in this case.

In carrying out the invention I provide a plurality of pairs of arcing horns 11, three sets being shown in the present instance as there are three suspended conductors, though it should be understood that there maybe fewer or more depending upon circumstances. One arcing horn is mounted at each of the bolt-like members 6 which support the strings of insulators,'and another in each set, is located at one of the bolt members 9 which secure the arms 7 in place. The exact mechanical construction of. these arcing horns is naturally a matter which may be varied within wide limits as'it is easily possible to make their bases 12 somewhat in the nature of nuts for the bolts 6 and 9. This arrangement would be very convenient and inexpensive and is indicated in the drawing. The horns are re resented-as of curved shape and extend toward each other be carried out in is probably immaterial, at least within certain limits. The most advantageous gap dis- J tance may be ascertained by experiment. By

this arrangement it is clear that certain of the horns are in electrical connection with the metallic suspension elements for the insulator strings while the others are in electrical connection with the metallic braces 7 These braces are intended to be grounded and this is readily done by means of conductors 15 connected therewith and brought down either inside or outside the poles and extending into the earth. For the sake of illustration, these ground wires or conductors are shown as wrapped about the bases of the poles as indicated at 16 though it is readily apparent that any other equivalent arrangement may be resorted to.

Assuming that the installation has been effected as shown and described, or in an equivalent manner, it is apparent that in the event of a lightning discharge, the charge will jump across one or more of the gaps 14 and be conducted to the ground, thereby protecting the wood against burning, shattering or rupture. The, protective system will operate equally well under wet or dry wood conditions and is extremely efficient as it -provides an easy path for the lightning flashover. Furthermore the arrangement is such as not to detract in any way from the insulating value of the wooden installation itself. It is believed that from the foregoing the construction, operation and advantages will be readily understood by one skilled in the art without further explanation.

While I have shown and described the preferred embodiment of the invention, it should be understood that the disclosure is merely an exemplification of the principles involved as the right is reserved to make all such chan es in the details of construction as will widen the field-of utility and increase the adaptability of the device provided such changes constitute no departure from the spirit of the lnvention or the scope of the claims hereunto appended.

Having thus described the invention, I claim:

1. In a supporting structure for transmission lines includin a wooden cross arm, a bolt passing throug said cross arm for supporting a string of insulators therefrom, and an arcing horn adapted to seat on said bolt and a cooperating arcing horn on said structure, said last named horn being connected to ground.

2. In a transmissionline system a support.- ing structure including a wooden cross arm, a string of insulators mounted thereon by means of a metallic bolt, and an arcing horn detachably connected to said bolt, another arcing horn connected to said arm by means of the arm supporting member, said last named horn, the adjacent portions of said horns being spaced apart sothat the insulating value of the air gap separating the same is less than that of said supporting structure.

4. In a supporting structure for transmission lines including a wooden cross arm, a string of insulators mounted thereon by means of a metallic connector and arcing horn adapted to be detachably connected to one end of said metallic connector, a brace for said cross arm connected to ground and another arcing horn electrically connected to said brace and spaced from said first named horn.

5. In a transmission line arrangement, a wooden supporting structure, insulators mounted thereon by means of metallic elements, and a plurality of arcing hornso'n said structure, certain of said horns bein grounded and others being in physical an electrical contact with said" elements, the horns being spaced apart to form limited air gaps.

In testimony whereof I afiix my signature.

GEORGE WELLINGTON HAMILTON. 

